REPAIRtoire - a database of DNA repair pathways

Welcome! Click here to login or here to register.
Home
Proteins
DNA damage
Diseases
Homologs
Pathways
Keywords
Publications
Draw a picture
 
Search
 
Links
Help
Contact





Bujnicki Lab Homepage

"Substrate specificity of the Saccharomyces cerevisiae Mus81-Mms4 endonuclease."

Fricke WM, Bastin-Shanower SA, Brill SJ



Published Jan. 3, 2005 in DNA Repair (Amst) volume 4 .

Pubmed ID: 15590332

Abstract:
Mus81-Mms4/Eme1 is a conserved structure-specific endonuclease that functions in mitotic and meiotic recombination. It has been difficult to identify a single preferred substrate of this nuclease because it is active on a variety of DNA structures. In addition, it has been suggested that the specificity of the recombinant protein may differ from that of the native enzyme. Here, we addressed these issues with respect to Mus81-Mms4 from S. cerevisiae. At low substrate concentrations, Mus81-Mms4 was active on any substrate containing a free end adjacent to the branchpoint. This includes 3'-flap (3'F), regressed leading strand replication fork (RLe), regressed lagging strand replication fork (RLa), and nicked Holliday junction (nHJ) substrates. Kinetic analysis was used to quantitate differences between substrates. High Kcat/Km values were obtained only for substrates with a 5'-end near the branchpoint (i.e., 3'F, RLe, and nHJ); 10-fold lower values were obtained for nicked duplex (nD) and RLa substrates. Substrates lacking any free ends at the branch point generated Kcat/Km values that were four orders of magnitude lower than those of the preferred substrates. Native Mus81-Mms4 was partially purified from yeast cells and found to retain its preference for 3'F over intact HJ substrates. Taken together, these results narrow the range of optimal substrates for Mus81-Mms4 and indicate that, at least for S. cerevisae, the native and recombinant enzymes display similar substrate specificities.


This publication refers to following REPAIRtoire entries:

Proteins


Last modification of this entry: Oct. 6, 2010

Add your own comment!

There is no comment yet.
Welcome stranger! Click here to login or here to register.
Valid HTML 4.01! This site is Emacs powered. Made with Django.